1. Field of the Invention
The present invention relates to an information processing system capable of transmitting files between computers in a network environment in which a plurality of computers are linked with each other, an information processing apparatus in the system, and a method of controlling the system and the apparatus.
2. Related Background Art
FIG. 1 is a view for explaining a file transmission method using general electronic mail. In a general mail transmitting operation in which no file is transmitted, the mail sender generates a mail message by using a mail tool 102, designates a receiver, and transmits the message to the receiver. A sending mail server 103 receives the message transmitted from the mail tool 102, and sends the message to a receiving mail server 104. The sending mail server 103 and the receiving mail server 104 are linked with each other by a mail transfer protocol such as SMTP (Simple Mail Transfer Protocol) on a computer network. A mail message is transferred in accordance with the protocol.
The receiver can extract mail addressed to the receiver by the receiving mail server 104 and check the contents of the mail by using a mail reader 105.
When a file is to be transmitted together with a message, the sender generates the message by using the mail tool 102 as in the above case. The sender then selects the file to be transmitted, merges it into the mail message, and transmits the message from the sending mail server 103.
When, for example, SMTP, which is a standard electronic protocol in the Internet, is to be used, the mail tool 102 generates a message called a multipart, which is constituted by a plurality of divided message portions, by using Multipart/Mixed type as Content-Type in the MIME (Multipurpose Internet Mail Extension) standards. The sending mail server 103 then transmits the divided message portions (multipart).
In this case, an attached file is one part of the multipart, and a file format can be designated as Content-Type for the part in the form of text/html or the like. Files of various formats can therefore be merged into a mail message and transmitted. The receiver can extract the attached file from the received mail by using the mail reader 105, and store the file in a disk. Then, the file can be displayed and edited by using various tools.
In general, the mail reader 105 holds a table indicating correspondence between Content-Types indicating the formats of attached files and tools for processing the files of the respective formats, and automatically activates a corresponding tool in accordance with operation performed by the receiver. For example, the mail receiver can set this table to activate a text editor for a text/pain file; a WWW (World Wide Web) browser for a text/html file; and the wordprocessor software xe2x80x9cWordxe2x80x9d (tradename) available from Microsoft for an application/msword file. With this setting, the contents of an attached file can be easily checked.
In addition, in a file transmitting operation using an xe2x80x9cattached filexe2x80x9d, a file can be transmitted by xe2x80x9cfile referencexe2x80x9d using electronic mail. According to the MIME standards, a transmission target file can be handled as external data, and the location of the file and a reference method for the file can be described in a mail message by setting Content-Type of mail header information as Message/External-Body type, instead of directly merging the contents of the file into the mail message.
In this case, the transmission target file is not transmitted as a mail message, but the receiving side will receive the target file by outputting a file transmission request by using another means in accordance with the location of the file and the reference method described in the mail message.
A file management/transmission unit 101 in FIG. 1 includes a file management unit (file system) for managing transmission target files and a file transmission unit for transmitting a file in response to an external file transmission request. Each file referred to as a transmission target is managed by this file management unit. The receiver uses the mail reader 105 to activate a file reception/display unit 106 in accordance with the location of the file and the reference method described in the mail message. The file reception/display unit 106 outputs a file transmission request to the file management/transmission unit 101, which is mounted in the computer to manage the file, on the basis of the location of the file described in the mail message, receives the contents of the file, and displays the contents.
Standard file transfer protocols such as FTP (File Transfer Protocol) and HTTP (Hyper Text Transfer Protocol) are used between the file reception/display unit 106 and the file management/transmission unit 101. The use of a specific protocol for file transfer is designated as a file reference method in the mail message, and the corresponding file reception/display unit 106 can be automatically activated by the mail reader.
The following problems, however, are posed in the above xe2x80x9cattached filexe2x80x9d type file transmission.
1) The problems posed when a file with a large size is to be transmitted or a file is to be transmitted to many receivers are:
1-1. A heavy load is imposed on the network resources between computers.
1-2. A heavy load is also imposed on the computer resources on the sending side.
1-3. Attached files having the same contents are one-sidedly distributed to receivers, and the management of transmitted files depends on each receiver.
2) When the contents of an attached file are based on a file format depending on a specific tool, an environment that allows the tool to operate must be prepared or the file must be re-transferred to the tool operation environment, resulting in a heavy load imposed on the receiver.
Furthermore, the following problems are posed in the above xe2x80x9cfile referencexe2x80x9d type file transmission.
3) A method of describing a reference method for an external file is limited to a standard method. That is, some restriction is imposed on the users.
4) Mail readers capable of accurately analyzing a file reference description method and activating the file reception/display unit 106 are not so popular.
The present invention has been made in consideration of the above problems, and has as its object to provide an information processing system, an information processing apparatus, and an information processing method which reduce loads imposed on computer resources, computer network resources, and users in file transmission using electronic mail.
It is another object to implement various extension functions and applications that are not implementable in the prior art in which a file itself is added to a mail message, thereby effectively using electronic mail.
It is another object of the present invention to obviate the necessity to expand and modify the electronic mail system itself, and to achieve the above objects while solving the problem of interconnection characteristics to which the utmost importance is attached in the electronic mail system.
It is still another object of the present invention to achieve the above objects by attaching a file in which an access method for a file is described, instead of attaching a file, analyzing the access method on the receiving apparatus side, and acquiring the file.
It is still another object of the present invention to perform file transmission/reception more efficiently by using a proxy server for file transmission/reception in accordance with the above attached file.
It is still another object of the present invention to allow a check on the validity of a file acquired in accordance with the access method described in an attached file by describing file attribute information in the attached file, thereby improving the reliability of file transmission.
It is still another object of the present invention to allow a file transmission record to be held and perform proper file transmission management.
It is still another object of the present invention to allow registration of destinations to which each file can be transmitted so as to improve the security in file transmission.
According to one aspect of the present invention, in order to achieve the above objects, an information processing system having the following arrangement is provided.
There is provided an information processing system capable of transmitting a file on a network, comprising:
generation means for, in generating mail data, generating an attached file in which an access method for a designated file is described;
communication means for transmitting/receiving, through the network, the mail data to which the attached file generated by the generation means is attached;
extraction means for extracting the attached file from the received mail data; and
acquisition means for acquiring the designated file through the network in accordance with the access method described in the attached file extracted by the extraction means.
According to another aspect of the present invention, an information processing apparatus used in the above information processing system is provided.
According to still another aspect of the present invention, a control method executed by the above information processing system or apparatus is provided.
According to still another aspect of the present invention, a computer readable memory storing control programs for implementing the above control method is provided.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.